Edgar Filing: ARCA biopharma, Inc.

Ownership Submission

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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(Print or Type Responses)

1. Name and Address of Reporting Person ^*

Â Atlas Venture Fund VII L P

2. Date of Event Requiring Statement (Month/Day/Year)
01/27/2009

3. Issuer Name and Ticker or Trading Symbol
ARCA biopharma, Inc. [ABIO]

(Last)

(First)

(Middle)

,Â 890 WINTER STREET, SUITE 320

4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

_____ Director	__X__ 10% Owner
_____ Officer (give title below)	_____ Other (specify below)

5. If Amendment, Date Original Filed(Month/Day/Year)

(Street)

WALTHAM,Â MAÂ 02451

6. Individual or Joint/Group Filing(Check Applicable Line)
___ Form filed by One Reporting Person
_X_ Form filed by More than One Reporting Person

(City)

(State)

(Zip)

Table I - Non-Derivative Securities Beneficially Owned

1.Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common Stock	1,402,163 ⁽¹⁾	D	Â

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.			SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Warrant to Purchase Common Stock	Â ⁽²⁾	10/10/2013	Common Stock	75,449 ⁽³⁾	$ 9.7406	D	Â

Reporting Owners

Reporting Owner Name / Address	Relationships
Reporting Owner Name / Address	Director	10% Owner	Officer	Other
Atlas Venture Fund VII L P 890 WINTER STREET, SUITE 320 WALTHAM,Â MAÂ 02451	Â	Â X	Â	Â
Atlas Venture Associates VII, L.P. 890 WINTER STREET, SUITE 320 WALTHAM,Â MAÂ 02451	Â	Â X	Â	Â

Signatures

Atlas Venture Fund VII, L.P. By: Atlas Venture Associates VII, L.P. Its General Partner By: Atlas Venture Associates VII, Inc. Its General Partner By:/s/ Kristen Laguerre Name: Kristen Laguerre Title: Vice President		02/05/2009
^**Signature of Reporting Person		Date
Atlas Venture Fund VII, L.P. By: Atlas Venture Associates VII, Inc. Its General Partner By: /s/ Kristen Laguerre Name: Kristen Laguerre Title: Vice President		02/05/2009
^**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 5(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	These shares are held directly by Atlas Venture Fund VII, L.P. Atlas Venture Associates VII, L.P. is the general partner of Atlas Venture Fund VII, L.P. Each of the Filing Persons disclaims beneficial ownership of the shares except to the extent of his or its pecuniary interest therein.
(2)	This warrant is immediately exercisable.
(3)	These warrants are held directly by Atlas Venture Fund VII, L.P. Atlas Venture Associates VII, L.P. is the general partner of Atlas Venture Fund VII, L.P. Each of the Filing Persons disclaims beneficial ownership of the warrants except to the extent of his or its pecuniary interest therein.
Â Remarks: ThisÂ statementÂ onÂ FormÂ 3Â isÂ filedÂ byÂ AtlasÂ VentureÂ FundÂ VII,Â L.P.Â andÂ AtlasÂ VentureÂ AssociatesÂ VII,Â L.P.Â Â TheÂ principalÂ businessÂ addressÂ forÂ eachÂ ofÂ theÂ reportingÂ personsÂ isÂ 890Â WinterÂ Street,Â SuiteÂ 320,Â Waltham,Â MassachusettsÂ 02451.Â Â TheÂ reportingÂ personsÂ disclaimÂ beneficialÂ ownershipÂ ofÂ theÂ securitiesÂ listedÂ hereinÂ exceptÂ toÂ theÂ extentÂ ofÂ theirÂ pecuniaryÂ interestÂ therein.

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